The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A multiple-speed automatic transmission commonly provides a single, high pressure hydraulic fluid pump to provide all flow of hydraulic fluid to the components of the transmission. Portions of the transmission such as the controls system require a high pressure, low volume flow of fluid. Other portions of the transmission such as the clutch assemblies and the torque converter require only a low pressure, but a high flow rate of hydraulic fluid. The single, high pressure hydraulic fluid pump therefore provides fluid flow at a pressure that must be regulated to a lower pressure for most uses, thereby inherently incurring system inefficiency.
The clutch assemblies of known automatic transmissions also commonly include rotating clutch members which require rotational seals. Rotational seals inherently leak, which provides a further system inefficiency and loss.
Thus, while current automatic transmission control systems achieve their intended purpose, there is a need for a new and improved system and method for reducing high pressure oil usage and thereby to improve fuel economy.